The Shabecoffs explore both the hazardous pollutants and the difficulties in preventing their hazard from the public. They plead "if we love our children, we should want to protect them, to give them a safe, healthy environment in which to be born and to grow up."

Almost one out of three children are reported to suffer from a chronic disease or debilitating birth defect because of the toxic chemicals and heavy metals in the environment. A baby born today has 150 to 230 toxic chemicals in his or her cord blood, including pesticides, PCBs, flame retardants, bisphenol A,  lead, and mercury (Hg).

Mercury and public health - "Children are particularly vulnerable to Hg intoxication, which may lead to impairment of the developing central nervous system, as well as pulmonary and nephrotic damage."[1] Counter and Buchannan, both of Harvard , Medical School and University Health Services, respectively, examine several sources of toxic Hg exposure in children that have been reported in biomedical literature:

(a) Methylmercury, MeHg, the most widespread source of Hg exposure, is most commonly the result of consumption of contaminated foods, primarily fish,

(b) Ethylmercury, which has been the subject of recent scientific inquiry in relation to the controversial pediatric vaccine preservative thimerosal,

(c) Elemental Hg (metallic Hg) vapor exposure through accidents and occupational and ritualistic practices,

(d) Inorganic Hg,  primarily mercuric chloride, through the use of topical Hg-based skin creams and in infant teething powders;

(e) Metallic Hg in dental amalgams, which release Hg vapors, and Hg2+ in tissues.

Each source of Hg exposure is reviewed in relation to specific pediatric health effects, particularly subtle neurodevelopmental disorders. The authors cover the most recent and ongoing large cohort longitudinal studies of MeHg intoxication in children, as well as contemporary studies of MeHg exposure in pregnant women who consumed varying amounts of fish, the primary source of MeHg intoxication. Accidental, occupational, and ritualistic exposure to Hg vapor in both modern and traditional societies was also explored. The toxic effects of inorganic Hg from the use of Hg-based topical cosmetics and teething powders, as well as from dental amalgams were examined.

On the cord blood: The "safe Hg level" in cord blood is considered to be 29 ppb. However, a threshold at which there are no apparent developmental effects of MeHg has not been established. Some studies have shown adverse effects even below 10 ppm.

Mercury and environmental health - Coal-fired power plants are the largest point source of anthropogenic Hg, contributing about one-third of the anthropogenic Hg released in USA. The Environmental Protection Agency (EPA) announced plans to regulate Hg emissions from coal-fired power plants. Brookhaven National Laboratory (BNL) with support from the Department of Energy prepared a quantitative assessment of the reduction in human health risk that could be achieved through reduction in coal plant emissions of Hg.[3]

The primary pathway for Hg exposure is through consumption of fish. The most susceptible population to Hg exposure is the fetus. Therefore the risk assessment focused on consumption of fish by women of child-bearing age. Dose response factors (DRF) were generated from studies on loss of cognitive abilities like language skills and motor skills by young children whose mothers consumed large amounts of fish with high Hg levels.

Population risks were estimated for the general population in three regions, the Midwest, Northeast, and Southeast, that were identified by EPA as being heavily impacted by coal emissions. Three scenarios for reducing Hg emissions from coal plants were chosen: (a) A base case using current conditions; (b) A 50% reduction; and, (c) A 90% reduction. These reductions in emissions were assumed to translate linearly into a reduction in fish Hg levels of 8.6% and 15.5%, respectively. Population risk estimates were also calculated for two subsistence fisher populations. These groups of people consume substantially more fish than the general public and, depending on location, the fish may contain higher Hg levels than average. Risk estimates for these groups were calculated for the three Hg levels used for the general population cases.

Results showed that the general population risks for exposure of the fetus to Hg are small. Estimated risks under "no specific Hg controls" ranged from 5.7 х 10-6 in the Midwest to 2 х 10-5 in the Southeast. Reducing emissions from coal plants by 90% reduced the estimated range in risk to 5 х 10-6 in the Midwest and 1.5 х 10-5 in Southeast, respectively. The population risk for the subsistence fisher using the Southeast regional fish Hg levels was 3.8 х 10-3, a factor of 200 greater than the general population risk. For the subsistence fishers and the Savannah River Hg levels, the population risk was 4.3 х 10-5, a factor of 2 greater than for the general population.

The estimated risk reductions from a 90% reduction in coal plant Hg emissions ranged from 25% to 68%, which is greater than the assumed reduction in Hg levels in fish, 15.5%.

Assuming that there are 4 x 106 births in a year (National Vital Statistics Report, 2000) and the Southeast risk level, i.e. the highest of the regions,  is same for the entire country, an estimate of 80 newborn children per year have a 5% chance of realizing any of the 16 adverse effects used to generate the DRF. If Hg emissions from power plants are reduced by 90%, the number of children at risk is reduced to 60.

If a more detailed risk analysis were carried out, BNL estimates that the number of children at risk would decrease because the Southeast region has the highest risk estimates but accounts for only 24% of the births in USA. They suggest that California, on the other hand, without coal-fired power plants and with only 12.5% of the children born in a year, would not benefit much from reduced emissions.

Health as Beauty Policy - Public health and environmental health are intimately related. Beauty requires health. The Shabecoffs discuss how the public and private institutions that are supposed to be looking out for the welfare of children are failing to protect them.

Counter and Buchanan's medical article on mercury exposure to children shows mercury poisoning in children is most commonly the result of consumption of MeHg-contaminated foods, primarily fish. The half-life of MeHg in the body is about 50 days with a range of 20 to 70 days, and in hair, the half-life averages about 65 days with a range of 35 to 100 days -- indicating that MeHg leaves the body slowly. Although MeHg is distributed throughout all of the organs of the body, it has its most devastating effect on the developing brain. In the adult brain, MeHg damage is focal, for example, involving a loss of neurons in the visual cortex and a loss of granule neurons in the cerebellum. In the developing brain, the damage is more diffuse and extensive.

BNL's Sullivan and colleagues had the objective to quantify risks from Hg exposure to the fetus through consumption of fish by its mother. Their study investigated the reductions in risk that might occur if Hg emissions from coal-fired power plants were reduced by 50 and 90%.

Examination of the distribution of population risks indicates that 99% of the population bears less than 0.2% of the total risk. The population risk is dominated by the 1% of the population with the highest hair Hg levels. The choice of DRF makes a substantial impact on risk in this case.


"Expert panels have estimated that it would take 15 – 25 years before the impacts of reduction in Hg emissions could be observed."

References

[1] Protecting Children From Toxic Chemicals, Chem Engng News, January 5, 2009 Volume 87, Number 1 pp. 34-36

[2] Mercury exposure in children: a review, S. Allen Counter, and Leo H. Buchanan, Toxicology and Applied Pharmacology 198 (2004) 209– 230

[3] BNL report BNL-71538-2003, Potential Health Risk Reduction Arising From Reduced Mercury Emissions From Coal-Fired Power Plants,  T.M. Sullivan, F.W. Lipfert, S.C. Morris, P.D. Moskowitz, Sept 2001